And they wouldn't with what I posted. Nightmare would be required to be BiS. And you wouldn't be able to buy highest rated gear like now. As it worked last tier, the new HMs and corresponding gear made NiM pointless from a gearing standpoint.
This is what you said,
So, say the next tiers of gear are 81 and 83, the layout would be:
New mythical HM Op - drop set bonus gear with lettered 83s
NiM - drop set bonus unlettered 81s
Comms - buy non-set bonus, lettered 81s
Did 81s become better than 83s at some point?
Not to mention you say to allow comms to buy NiM tier gear.
Anyways, carry on.